Is it possible she strained her right arm as well? This could cause bruising. There are no specific medicines for bruises. I am concerned that the bruising is occurring without obvious injury. It could be a sign of a bleeding disorder or something wrong with the platelets in her blood. When I have a patient who develops spontaneous bruising like this, I work them up for a bleeding or clotting disorder, and for abnormalities of the blood cells. This is done with blood tests. Depending on the test results, I might then have my patient see a hematologist, who specializes in disorders like this. Unless there is an obvious cause for the bruising, I would not start out with just treating it. Hope I have answered your query. If you have any further questions I will be happy to help.